Struggling With Tuning MAFT 2.xx

[jfdid]

Well, time for an FMIC I suppose.

I switched to Husky 92 octane gas and it's made a fair difference, for sure. I'm partially bucking, and partially knocking on this new gas. So, some hope is to be had.

For anyone switching gas: you'll have to go through at LEAST 2 fillups to notice the full difference. I went through about 120 dollars worth of gas(the same brand) before I got rid of all of the other stuff in there. Suprised me QUITE a bit, for sure.

Keep up with the replies.

As far as the timing maps go: DSMLink I suppose is the way to go with that. I can't wait for the 1g edition. WEEEEE

 

[98spydert]

I have had my share of nightmares with MAFT as well. Once interesing find that I made, is that my A/F ratios change drastically from day to night. The temp. difference from day to night varies as much as 40' here, and GM MAFT doesn't have any kind of temp. compensation, since it's preset. This might actually affect car's response quite a bit. I can run 22psi with no knock during day time, but come night, I'm knocking badly.. Obviously re-tuning it every day and night is not most pleasant.

Has anyone else experienced and temp-related anomalies?

Temp shouldn't be an issue at all. The GM sensor measure the temp indirectly, through density basicly. Read up on how the hot wire style maf works and you'll understand.

 

[Newlogics]

Temp shouldn't be an issue at all. The GM sensor measure the temp indirectly, through density basicly. Read up on how the hot wire style maf works and you'll understand.

That makes sense, but for some reason I'm still seeing very different values from 60' to 20' outside temp... I don't have anything else to blame but translator... Am I missing something here ?

 

[honduraneclipse]

i just started tuning my friends 94 talon. the weather does change the way the car wants to run. at day time my friend runs 13lbs. of boost with no sputter,backfire or cutoff. but at nighttime the cold dense air makes the car run more lean which then we would have to richen it up at mid and wo throttle. this is the reason why we are going to run the translator into the cockpit.

 

[Talonman]

seems like a 2G MAF and safc is more foolproof up to 450hp and above that you should be considering dsmlink or stand alone anyway? Is the possibility of pshhht between shifts worth it?

 

[talon_boy69]

Temp shouldn't be an issue at all. The GM sensor measure the temp indirectly, through density basicly. Read up on how the hot wire style maf works and you'll understand.

That's true, but for some reason cars factory equiped with hotwire also have an IAT sensor.

 

[psychlow]

Question for all you MAFT users experiencing problems -

Do any of you have the screens removed from the MAF? Does fullthrottlespeed even ship them with the screens installed?

In front of the heated wire is a screen. Many people are suggesting that improved airflow will be gained by cutting the screen out of the MAF. It is not recommend that this be done on an F-body. Most people mistake this screens purpose as preventing debris from hitting the hot wires in the MAF (that is what the air filter is for). Actually the screen is a bank of straightening vanes used to straighten the airflow before passing by the hot wires. Eddies and vortices (turbulence) in the MAF will cause inaccurate readings. Straightening vanes are used in most mass flow measurement situations where 10 diameters of straight upstream conduit are not available. The F-body intake does not meet this requirement.

An accurate MAF sensor is critical for the engine's fuel/air ratio adjustments. So, what happens when the screen is removed? The flow (mass) is the same, BUT without the screen (which is a restriction) the velocity is lower. Lower velocity means a hotter wire temperature which equates to a LOWER flow! So the PCM adjusts the injectors to provide LESS fuel. Since the HO2 sensors do not provide input when the MAF is online the PCM does not adjust for the LEAN condition, until it goes back into Closed Loop Condition.

This may account for differences in performance with varying temperatures if the screens aren't there, especially if the MAF is mounted shortly after a bend in IC piping.

 

[TSI_FWD]

I have the screen in mine and I am experiencing exact same symptoms as described in previous posts.

 

[talon_boy69]

I also have mine

 

[talon_boy69]

anyone with the problem tryed or actually using 1.3v maft or drawtrhough instead of blow through?

 

[jfdid]

An update: since I moved the MAFT inside, i've spent a lot more time tuning the car, and I can tell you this: NOTHING.

The WOT mode is good, and I can tune the car pretty well, until the weather/temperature changes. Then I'm outta luck again. I can only assume the weather is the problem, as nothing else changes overnight.

The only other theory is that intercooler. Because I'm running drawthrough, the sensor may read one temperature, then the air travels through a heatsoaked cooler, thus, changing the density/count. I wonder if blowthrough would help?

I've got alchy injection sitting at home right now, it'll be in in a couple weeks. Hopefully that can make up for a little bit of the IC problem.

Otherwise, a keydriver chip to compensate for the timing is probably coming. Or DSMLink, if the 1G version is out yet?

 

[DSMcamaro]

I know this thread is really old, but does anyone have any updates? I think I'm experiencing some similar issues.

 

[jfdid]

Easiest way to fix those problems is to quit running such huge injectors. The stock ECU does NOT like anything bigger than 600cc injectors coupled with the MAFT. You are taking so much of the airflow signal, you are sending the timing maps thru the roof. Put your 450's in and take a drive. See how much timing you initially get. Then put in your 660/750's and set the MAFT for those. IF you can get the car to move, look at your timing. That's the problem. That is why the car bucks so bad when you first take off. Way too much timing advance initially.

It's been a LONG time, but I put the car back on the road. I put the 450's in and watched my timing, then the 680's and I'm running about 20, yes 20 more degrees with the 680s, which explains the knock absolutley.
Next up is a DSMlink, an FMIC and hook the water/meth injetion back up.

Seriously though, for others reading - I struggled with this tune for over a year and got so frustrated that I took the car off the road for a year and a half. Spend the money on a DSMlink, or at very least, a chip for your injectors so you can stop banging your head against the wall.